PSA: LoL is a Privilege, Not a Right
Because there seems to be a ton of people lately who don't understand why it is perfectly reasonable for RIOT to permanently ban their account or disqualify them from rank rewards due to punishment, I'll leave a simple explanation.
Playing League of Legends is a privilege given to you by RIOT, not a right you earned (or bought, for those complaining about how much money they've spent). As with any other privilege, it can be taken away by RIOT at any time for any reason they decide on. The Terms of Service that you agreed to not only when you first downloaded the game but every single patch afterwards explicitly states this; the account is RIOT's, not yours, and they can take it back any time they choose to. In fact, permanent bans are RIOT's way of saying they don't necessarily want you playing the game anymore because you have either shown no signs of reforming after multiple punishments or are so toxic that they simply decided to escalate you in hopes of sparing the community of your presence.
Same goes with rank rewards; RIOT doesn't hide the fact that any punishment will cost you the privilege of receiving these rewards, no matter how much you feel you "earned" them.
If you choose to stick around after punishment and/or losing rewards, I sincerely hope you take this lesson to heart and begin acting like a rational human being. You don't have to be a care-bear or anything, just "don't be a dick" as the player behavior team has been known to say. Is a teammate feeding, or another player is trolling? Scream into your monitor, bitch to your Discord friends, or do anything else that doesn't involve you insulting or trolling in-game. To me it'd be even better to not have a negative mindset at all, even if it's not directed at the other nine players, but that's another story.